Max iterations best trade-off

Hello community,

I’m looking for a strategy to determine the optimal max iterations value “vra.setMaxIterations(maxIterations)” : trade-off between best final results and lowest time to process jsprit.

I guess it depends on the used algorithm and the number of visited node, am i correct?

For instance, it is not necessary to use a high max iterations for simple problem.

Thank you,
Martin

No answer, nevermind, max iterations is an algo parameter…

By the way, on jpsrit 1.6.2, to build a problem :

final VehicleRoutingProblem vrp = vrpBuilder.build();
final VehicleRoutingAlgorithmBuilder vraBuilder = new VehicleRoutingAlgorithmBuilder(vrp, xml_file);

On jsprit 1.7.0, VehicleRoutingAlgorithmBuilder doesn’t exist anymore, did you remove xml configuration way? Now the appropriate way is to configure algo by coding?

Yes, configure it in code like this: https://github.com/graphhopper/jsprit/blob/master/jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/box/SchrimpfFactory.java#L55

Unfortunately, you need to find out yourself. Just conduct a sensitivity study based on your problems with varying max iterations. For very simple problems, you dont need many iterations. However, you can also use a number of termination strategies you can find here: https://github.com/graphhopper/jsprit/tree/master/jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/termination. For example, VariationCoefficientTermination terminates the algo if variations of costs of found solutions are less than a threshold variation.

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BTW: you can still use the xml config by using the jsprit-io module. It is just removed from the core.